Marine Ecosystem Dynamics Modeling Laboratory

Climatologic Mean

1. Monthly climatologic fields of water temperature and salinity

We have built a monthly climatologic field of water temperature and salinity in the Gulf of Maine/Georges Bank region with extension to cover the Mid Atlantic Bight. The data source comes from 1) Bedford Institute of Oceanography (BIO) hydrographic database, 2) NMFS hydrographic database, 3) US GLOBEC/GB hydrographic database and 4) the New England shelf-break hydrographic database created by C. Linder, and G. G. Gawarkiewicz at WHOI. All data were first processed with quality control and then averaged in a regular 10×10 km2 box. To resolve the sharp cross-isobath gradient of water temperature and salinity related to the shelf break front, a vectorized averaging with a long-correlation scale along the isobath a short-correlation scale across the isobath was conducted in the shelf break region.

Examples of the monthly climatological distributions of near-surface water temperature and salinity can be viewed in animations 1-2.

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Monthly Averaged Salinity

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Monthly Averaged Temperature

Examples of the cross-bank distributions of water temperature and salinity can be viewed in animations 3-4.


Salinity


Temperature

2. Monthly climatologic fields of the subtidal circulation

The monthly climatologic field of the subtidal circulation was build on the residual circulation field output from FVCOM runs with initial condition of monthly climatologic water temperature and salinity. Two experiments were made: 1) the case with the M2 tidal forcing only and 2) the case with the M2 tidal forcing plus monthly averaged QuikSCAT wind stress (with spatial distribution). QuikScat data used here include all available calibrated wind fields starting in 1999.

Unlike the climatologic fields shown in previous modeling efforts using QUODDY Naimie et al. 1994; Naimie, 1996) and POM/ECOM-si (Chen et al., 2001), we have included a spatial distribution of the monthly-averaged wind field in FVCOM experiments. The comparison with previous model results suggests that the spatial variation of the wind field plays a significant role in the monthly climatologic field of the near-surface subtidal circulation in spring through summer.

It should be pointed out here that the true monthly-averaged circulation of the subtidal circulation in the GoM/GB region is significantly different from the monthly climatologic fields of the subtidal circulation predicted based on this traditional numerical approach. One should be caution in applying the model results shown here to interpret the in-situ field measurement data or using them to study the fishery recruitment issue. This is why we need a model that is capable to produce a short-term and also a long-term variability of the circulation in the GoM/GB, rather than building our understanding of the seasonal variability of the circulation based on gathering of the climatologic field predicted by climatologic forcing fields.

3. QuikSCAT winds

The QuikSCAT data shown here were download directly from the NASA JPL QuikSCAT level 2 database. It must be caution in using these data because the wind direction might be incorrect during air-frontal passages. For detailed explanation, please conduct Dr. Chen at SMAST or Dr. Beardsley at WHOI, who has made a direct comparison between MM5-predicted and QuikSCAT wind fields in the GoM/GB region.

Example of QuikSCAT wind data available for the Gulf of Maine/Georges Bank region

Period: July-December,1999;

January-October 2002

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Posted on January 17, 2014